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<div class="titlepage"><div><div><h4 class="title">
<a name="phoenix.modules.scope.local_variables"></a><a class="link" href="local_variables.html" title="Local Variables">Local Variables</a>
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<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">phoenix</span><span class="special">/</span><span class="identifier">scope</span><span class="special">/</span><span class="identifier">local_variable</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
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<p>
          We use an instance of:
        </p>
<pre class="programlisting"><span class="identifier">expression</span><span class="special">::</span><span class="identifier">local_variable</span><span class="special">&lt;</span><span class="identifier">Key</span><span class="special">&gt;::</span><span class="identifier">type</span>
</pre>
<p>
          to represent a local variable. The local variable acts as an imaginary
          data-bin where a local, stack based data will be placed. <code class="computeroutput"><span class="identifier">Key</span></code> is an arbitrary type that is used
          to identify the local variable. Example:
        </p>
<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">size_key</span><span class="special">;</span>
<span class="identifier">expression</span><span class="special">::</span><span class="identifier">local_variable</span><span class="special">&lt;</span><span class="identifier">size_key</span><span class="special">&gt;::</span><span class="identifier">type</span> <span class="identifier">size</span><span class="special">;</span>
</pre>
<p>
          <span class="bold"><strong>Predefined Local Variables</strong></span>
        </p>
<p>
          There are a few predefined instances of <code class="computeroutput"><span class="identifier">expression</span><span class="special">::</span><span class="identifier">local_variable</span><span class="special">&lt;</span><span class="identifier">Key</span><span class="special">&gt;::</span><span class="identifier">type</span></code>
          named <code class="computeroutput"><span class="identifier">_a</span></code>..<code class="computeroutput"><span class="identifier">_z</span></code> that you can already use. To make
          use of them, simply use the <code class="computeroutput"><span class="keyword">namespace</span>
          <span class="identifier">boost</span><span class="special">::</span><span class="identifier">phoenix</span><span class="special">::</span><span class="identifier">local_names</span></code>:
        </p>
<pre class="programlisting"><span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">phoenix</span><span class="special">::</span><span class="identifier">local_names</span><span class="special">;</span>
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